Extinct Pleistocene Mammals 419 



covery in the eighth annual report of the Geological Survey of the 

 state, and from it are taken the following facts: 



The specimen was eight feet below the surface, under the sandy 

 loam that lies on the brick clay, and about 20 feet above the level of 

 the river, near the bottom of the sand and gravel. It was accom- 

 panied by some Unio shells. Its relation to the gravel, and to the 

 topography of the valley, indicates that the animal inhabited the 

 region when the border of the ice-sheet had already retired to the 

 northward of Minneapolis, but that the river was maintained at a 

 maximum flood stage by the dissolution of the ice fields that lay 

 further north, and probably covered the northern part of the state. 

 That is, it was cotemporary with the closing stages of the Wisconsin 

 epoch. The specimen found at Minneapolis is preserved in the mu- 

 seum of the University. It consists of the left ramus and the lower 

 left incisor. Its size indicates an animal somewhat larger than the 

 specimen first found in Ohio and described by Foster, and also larger 

 than that fcund in New York. It is however a little smaller than 

 that described by Wyman from Memphis, Tennessee. The whole length 

 of the speciraen, when the parts are united, is 9i/^ inches, of which 5^ 

 inches consist of the projecting, uncovered incisor, a portion of the 

 jaw having been broken away on the under side. The jaw contains 

 four molars, perfectly preserved. Their outer surfaces are finely 

 striated perpendicularly, and crossed transversely by undulations of 

 growth, while the great incisor is externally grooved longitudinally 

 with eighteen or twenty grooves, which are about twice as wide as the 

 ridges that separate them. The four molar teeth have a structure 

 like that of elephant's teeth, i. e., they are composed of transverse 

 hollow lamellae of enamel, embedded in a cementum, which also seems 

 to fill, at least originally, the interior of the lamellae. 



According to Prof. A. J. Allen the Castoroides cannot be put into 

 the same family as the modern beaver, but has affinities that ally it 

 with the chinchilla, the vescacha, as well n.s the muskrat. The entire 

 skeleton has never yet been found. It ranged over the whole United 

 States, from South Carolina to New York and to Mississippi, and from 

 Texas to Minnesota. l l 



3. Ovihos cavifrons. In 1903 the skull of the musk ox was 

 found by Mr. J. W. Franzen, now curator of our museum, where he 

 has kindly placed the specimen. This discovery was made on the 

 farm of Mr. McCracken, between Wabasha and Theilman, near the 

 railroad from Wabasha to Zumbr^ta. The specimen was about ten 

 feet below the surface, in a gravel terrace, of the valley. By Mr. 

 Franzen I have been furnished with the accompanying photograph of 

 this specimen. It consists of a skull, but v/ithout any teeth. The 

 broad horn cores are conspicuous, but they do not embrace any of the 

 curving horn torminations. The whole specimen is considerably 

 worn and reduced so as to have lost most of its projecting angularities. 



It belonged to a small animal, probably not mature: width trans- 

 verse 0V2 in., extreme width, including the horn cores, 8^^ inches, 

 length, front to rear 8^ inches. 



The region in which this specimen was found is within the "drift- 



